The group that challenged the heroes was to be called the 'League of Evil', led by Captain Marvel's nemesis Doctor Sivana. When the Challenge of the Super Friends season was originally conceived, it was named Battle of the Superheroes and featured the introduction of Captain Marvel to the Super Friends. The episode 'History of Doom' showed that Lex Luthor assembled 12 supervillains in order to form the most powerful and sinister group the world had ever seen. Other times, the Legion of Doom (or portions of it) would end up apprehended. In some episodes, they would escape capture through a last-minute escape plan often contrived by Luthor. In each episode of Challenge of the Super Friends that they appeared, the Legion of Doom would enact a plot against the Super Friends and a plot to take over the world only to be met with defeat by the end of the story. The Legion of Doom has since been incorporated into the main DC Universe, appearing in comics, as well as further animated and live-action adaptations, and also video games.

The Legion of Doom is a group of supervillains who originated in Challenge of the Super Friends, an animated series from Hanna-Barbera based on DC Comics' Justice League.

( Challenge of the Super Friends, Episode 1, September 9, 1978) The Legion of Doom members from left to right: Black Manta, Giganta, Toyman, Riddler, Bizarro, Scarecrow, Lex Luthor, Captain Cold, Cheetah, Solomon Grundy, Gorilla Grodd, Brainiac, and Sinestro.

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